My dad built me a bookshelf-kinda-thing specifically for them about 4 years ago; it's now referred to as a game-shelf, if that's a thing.
5 rows, 26 modern game cases fit on each (originally only planned to be 25, but hey, I'm not complaining).
I keep them in alphabetical order, by system. Save for the top shelf which is more for my "favorites," it's still organized alphabetically and by system as well, but it's more focused on holding the things I'm prone to grabbing the most. My Resident Evil collection, for example, goes up there, lol. And this drives my boyfriend nuts when he has to put one back.
Nothing else special. No fancy cases, just the ones they came in.
Though it's quite full, haha. I have piles of disc cases, shoeboxes of N64 games, and weird Gameboy game cases lying around my closet because they don't all fit on it or in it. The only systems' games that I'm 'displaying' are Dreamcast, Gamecube, PS2, 360, Wii U, DS, and 3DS games.. and the few PS1 and Xbox games I got for my PS2 and 360. Everything else is in my closet, and even some games from those systems are stuffed in there, too.
I mentioned to my dad that I'm gonna need a bigger one soon, and he was dumbfounded that I even have 100 games to put on it. Across the 7 systems whose games even fit on it in the first place. :pink_confused:
At least my PC games are digital. I just don't have the space, lol.